Impact of Polymer Composition and Salt Concentration of Poly(ethylene oxide)/Poly (methyl methacrylate)/Salt Blend Polymer Electrolyte

Poly (ethylene oxide) (PEO) based solid polymer electrolytes (SPEs) have been widely investigated due to their high lithium salt solubility. However, low mechanical strength and high crystallinity limits the performance of PEO based SPEs. Blending PEO with poly(methyl methacrylate) (PMMA), a high glass transition temperature polymer, is an effective method to improve mechanical stability and reduce crystallinity of SPEs. In this study, PEO/PMMA/lithium salt (lithium bis (trifluromethanesulfonyl)imide (LiTFSI)) blend SPEs were prepared by solution casting at various polymer composition and salt concentrations. The impact of salt concentration and polymer composition on the thermal and electrochemical properties of the resulting SPEs was evaluated. Results show that increasing salt concentration leads to reduced degree of crystallinity and higher ionic conductivity. SPEs with varying polymer composition exhibit similar ionic conductivities at the same salt concentration.